I get a little excited around middle school girls

Umm it depends???

Completely normal. However, if you're in a part of the world that criminalises acting on these urges you'd do well to avoid such activities.

So you are saying you feel terrified of and are threatened by adult women, but feel like a big man around little girls?
There's a word for that isn't there?

To be honest, I do to

Yeah they're awkwardly cute, but if you mean sexually excited it's ok if you don't act on it.

Normal if you are also a middle school girl

I also like middle school girls, they are just transitioning from being little girls to transforming into young women, and their body and mind is going through a lot of changes. They are just beginning to learn about their own sexuality and experiencing puberty and hormones. It's a very wonderful time in every young woman's life.